Ink drop printer



Feb. 13, 1968 R. A. ADAMS INK DROP PRINTER Filed June 10, 1964 ,22 ,26 ELECTED SOURCE MECHANKAL OF )0 TRANsDucER OSCILLA'HONS RESERVOIR OF \NK UNDER PRESSURE l SYNC. VIDEO 1 2O SIGNAL 52 5OURCE. 34 32 2 42 v V 46 SOURCE I m4;

+V2 561 VOLTAGE 38 l iDOLARCE sur'ePLus 5 l\ RESERVOR 1 1 I v j I1 q. 2

PATH OF DROPS 42 52 6o PU$H-PULL PULFDE VIDEO SOURCE SIGNAL. SOURCE 62 +2 28 72:::::: 5UF2PLU5 \N\( 0000: 6Q [8 lil- Z1 a; 3J4 2.) 76

L usH-wuLL PULSE soulQcE INVENTOR. /\7OMA/V A. ADAMS AMML United States Patent 3,369,252 INK DROP PRINTER Roman A. Adams, Skokie, IIL, assignor to The A. B. Dick Company, Chicago, III., a corporation of Illinois Filed June it), 1964, Ser. No. 374,135 12 Claims. (Cl. 346-75) ABSTRACT OF THE DISCLOSURE A system for writing is provided using ink drops which are projected from a source through a video charging tunnel to be selectively given a video charge. Thereafter, the drops pass between a biased pair of deflection plates which change the path of charged drops and permit uncharged drops to pass straight through. The uncharged drops are caught in a reservoir. The charged drops which remain pass through a second pair of deflection plates between which also is a sheet of the writing medium. Pulses from a source are applied to the second pair of deflection plates. These pulses are synchronized so that a line of the charged drops is deflected onto the writing medium. The line of drops has a pattern which is determined by the video signals.

This invention relates to printing apparatus and more particularly, to improvements in ink drop printing apparatus.

A considerable number of different approaches have been taken to the problem of printing from data signal sources at high speeds. Electrostatic techniques, as well as xerographic techniques, which are used presently, while providing high speed printing, require the use of expensive electrostatic paper. Another favorite arrangement for high speed printing is to employ apparatus termed a drum printer wherein solenoids actuate hammers which drive paper against an ink ribbon which in turn is driven against a rotating drum having type characters over the surface thereof. The nature of the equipment employed is rather expensive. Accordingly, efforts are still being made, despite the fact that high speed printing equipment is available, to find relatively inexpensive apparatus which can print at high speeds or even at medium speeds, on

.the order of 1,000 characters per minute, which also employ inexpensive paper.

An object of this invention is the provision of an inexpensive high speed printer which does not require expensive paper.

Another object of this invention is the provision of a high speed printer which does not employ expensive apparatus for printing.

Still another object of the present invention is the provision of a novel, and useful and relatively simple printing apparatus.

These and other objects of the present invention may be achieved by apparatus comprising a means for forming a train of uniformly sized and spaced ink droplets. In one embodiment of the invention, these ink droplets pass through a charging electrode wherein they are selectively charged, depending upon the presence or absence of a "ice video signal. The droplets then pass through a fixed electric field which deflects those of the droplets which have a charge and does not affect the others. The uncharged droplets then may be caught and removed while the deflected droplets continue beyond the influence of the deflecting field to a second region. At this point, the deflected droplets present a pattern (the absence or presence of drops) which is representative of the input video signal. This second region is also defined by opposed deflecting electrodes between which there is positioned paper. At an appropriate time, a voltage pulse is applied to these deflecting electrodes which establishes a field which causes the drop pattern to be deposited on the paper. The paper is then moved to receive the succeeding drop pattern. In this manner, characters may be formed on the paper as it is moved through the region of the depositing electrodes. In a second embodiment of the invention, the ink droplets receive a positive or negative charge from a push-pull video signal source. Thereafter, they pass between deflecting electrodes and paper is provided adjacent each electrode. Upon the application of a voltage pulse, positively charged droplets are deflected onto one sheet of paper and negatively charged droplets onto the other. One sheet of paper will then have a negative and the other a positive image of the video signal.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a block schematic drawing of an embodiment of the invention.

FIGURE 2 is a block schematic drawing showing fur ther details of the arrangement of FIGURE 1.

FIGURE 3 is a schematic drawing showing how negative printing may be achieved in accordance with this invention.

Referring now to FIGURE 1, in accordance with this invention there is provided a reservoir 10 which contains ink under pressure. The ink is allowed to be discharged from the reservoir through a pipe 12 which is coupled to a nozzle 14. The tip 16 of the nozzle may have an opening therein on the order of 1 mill or less, so that the ink which comes out of the opening is in the form of a thin stream 18.

The nozzle is vibrated at an ultrasonic frequency, such as kc., by way of example. This has the efliect of causing the thin stream of ink 18 to break up into droplets 20 which have a uniform mass and are uniformly spaced from one another. The mechanism for vibrating the nozzle 14 may be, for example, an electromechanical transducer 22 which is coupled by any suitable means, such as a coupling 24 to the nozzle 14. The electromechanical transducer is driven from a source of oscillations 26.

A small hollow cylinder 28 is positioned so that the ink drops, which are formed at the end of the ink jet 18, will pass through the center of the cylinder. Both the cylinder 28 and the nozzle 14 and/or ink are made conductive, and the cylinder and nozzle are connected to a as video signal source 39. The video, which is applied from the signal source 30 is synchronized from the source of oscillation. The drop formation is also synchronized from the source of oscillation. Accordingly, a drop which passes through the cylinder 28 will receive a charge, or not, from the video signal source which is synchronized with the drop formation. Alternatively, synchronizing signals may be derived from the video signals. These signals may then be used to vibrate the nozzle to thereby insure drop formation synchronization with the video signals.

After passing through the cylinder, which may be considered as a charging cylinder, the drops are permitted to pass between deflecting plates 32, 34. A steady DC voltage from a voltage source 36 is applied across these two deflecting plates thereby establishing a steady electric field between the two plates. Those drops which are not charged by the charging source 28 continue through the electric field in a straight line trajectory, being unaffected by the field, and are collected by means of receiving tube 355 which is connected to the surplus ink reservoir 40. From here, if desired, they can be returned to the reservoir 1%. Those of the drops which have a charge are deflected by the electric field between th plats 32, 34, into a path which takes them between two deflection plates 42, 44.

On the surface of the lower deflection plate 44, paper 46 is passed. Referring to FIGURE 2, there may be seen the details of the manner in which the pap-er is caused to pass betwen deflection plates 42 and 44. The paper is fed from a payoff roll 47 onto a take-up roll 48. The path of the poper between the rolls passes between the deflection plates 42, 44. The take-up roll is driven by a synchronized paper drive motor 59 which is synchronously driven by a pulse source 52. The pulse source is also connected to the deflection plates 42, 44.

It should be appreciated at this time that, as a result of the charge applied to each of the drops 20 from the video signal source, and the separation of the charged and uncharged droplets by means of the electric field deflecting plates 32, 34, the drops which reach the region between the two deflecting plates 42, 44, have a sequence pattern (the presence or absence of drops) of the input video signal. Therefore, upon the application of a pulse of the proper polarity from the pulse source, which is applied at the appropriate time to the deflection plates 42, 44 the ink droplets between them are thereby deflected downward onto the paper. Thus, if the video signal source provides video signals of the type which are derived by the successive line scan of printed material, and if a deflection pulse is applied from the pulse source 52 to the plates '42, 44 each time a line 'of droplets is positioned therebetween, and if the motion of the paper 46 is synchronized so that the paper is moved a suitable amount after the deposition of the line of ink droplet, then, the characters or pattern represented by the video signals will be written in ink on the surface of the paper, as represented in FIGURE 2. By a line of ink droplet is meant ink drp lets that represent a line of video signals. To insure the proper applications of pulses from the pulse source 52, these may be synchronized also from the same source of oscillations 26 as synchronizes the video signal source and forms the droplet.

It should be appreciated that the forward motion of a droplet through the two deflecting fields rises principally as a result of the emission of the ink stream 18 under pressure. Thus, it can be that a limitation will occur on the length of a line of drops which can be handled between the two deflecting plates 42, 44. This situation can be easily taken care of by giving the paper 46 a motion in the direction of the incoming line of drops, deflecting the incoming drops until the line of drops corresponding to a line of video signals has been deposited, then advancing the paper for receiving the next line of drops while returning the paper back to commence advancement again. However, by increasing the pressure in the ink res ervoir 10, the length of the line of drops that can exist between the plates 42, 44, may be easily increased.

FIGURE 3 illustrates a modification of the embodiment of the invention shown in FIGURE 1 to enable a negative and positive print to be produced. There is shown the end of the nozzle 14 which has the tip 16. The mechanism for applying ink under pressure, as well as for vibrating the nozzle and tip is the same as is shown in FIGURE 1. Spaced from the tip a distance equivalent to the location at which the stream under pressure, which is vibrated,

egins to break into uniform droplets, is the charging cylinder 28. A portion of the cylinder is omitted in order to show how the ink stream 18 forms into uniform mass droplets within the cylinder 28. A push-pull video signal source 60 is connected between the conductive nozzle and the charging cylinder 2-8. The purpose of the push-pull video signal source is to apply either a positive or a negative charge as determined by the video signal to the ink droplets passing therethrough. Alternative to the pushpull video signal source 60, for accomplishing the same results, there may be used a single-ended video signal source which produces at its output, negative and positive voltages in response to the video signals.

The fixed deflecting field may be omitted here and the droplets are permitted to continue in a path which takes them directly between two deflecting electrodes respectively 62, 64. Interposed between the electrodes 62, 64,

and adjacent thereto, there is passed two sheets of paper,

respectively 66, 68. This paper is on both sides of the path of the droplet through the electrodes instead of only on one side, as shown in FIGURES l and 2. However, the paper may be handled in the same manner as has been described in connection with FIGURES 1 and 2.

A push-pull pulse source 70 is connected across the deflection electrodes 62, 64-. This is energized to apply opposing polarity pulses to the deflecting electrodes 64, 62 whenever a line of ink drops has been inserted between these electrodes. When this occurs, the negatively charged ink droplets 72, will be directed toward the positively biased electrodes and be deposited out on the paper, and the positively charged ink droplets 74 will be directed to the negatively charged electrodes 64 and deposited out on paper 68. Any surplus ink which is not attraced and deposited out on the paper will be caught by a surplus ink reservoir 76, which is positioned on the side of the electrodes from which the droplets will exit.

As indicated, the push-pull source is actuated at the appropriate time which is delayed from the time that the end of a line of video signal occurs, long enough to permit a complete line of charged droplets to position themselves between the deflecting electrodesv In this manner, both a positive and a negative image of the video signal is produced. Other arrangements for charging the ink roplets may be employed. Two independent patterns may be derived by charging every second drop which has a positive charge, or none at all, and simultaneously charging the alternate drops negatively, or not at all. The drops that are not charged can pass undeflected through the plates to the surplus ink reservoir container. The pulse source can therefore be synchronized from the video signal source. As previously described, the vibrations applied to the nozzle should also be synchronized with the videosignal source.

There has been accordingly described and shown herein a novel, useful system for reproducing information which is contained in video signals using ink droplets.

What is claimed is:

1. A system for writing with ink in response to video signals comprising means for forming and directing a moving single file stream of uniformly spaced ink droplets each having a uniform mass along a predetermined path, means for charging said ink droplets responsive to said viedo signals with a charge having a polarity determined by the polarity of said video signals, a pair of spaced deflection electrodes positioned opposite one another on either side of the path of said charged droplets, a writing medium positioned between said deflection elec trodes and on one .side of the path of said charged droplets, and means for periodically applying a voltage pulse to said deflection electrodes to drive ink droplets therebetween to the surface of said writing medium.

2. A system for writing with ink in response to video signals comprising means for forming and directing a moving single file stream of uniformly spaced ink droplets each having a uniform mass along a predetermined path, means for charging said ink droplets responsive to said video signals with a charge having a polarity determined by the polarity of said video signals, a pair of spaced deflection electrodes positioned opposite one another on either side of the path of said charged droplets, a first writing medium positioned between one of said deflection electrodes and the path of said charged droplets, a second writing medium positioned between the other of said deflection electrodes and the path of said charged droplets, and means for periodically applying a voltage pulse to said deflection electrodes to drive ink droplets therebetween having one polarity to the surface of said first writing medium and ink droplets having the opposite polarity to the surface of said second writing medium.

3. In a system of the type wherein ink droplets are successively and uniformly formed and are directed along a path through a charging cylinder for applying a charge to said droplets in accordance with video signals, the improvement comprising a pair of spaced opposed elongated deflection electrodes positioned with one electrode on either side of the path of said ink droplets after passing through said charging cylinder, a writing medium positioned between one of said electrodes and the path of said ink droplets between said deflection electrodes, and means for periodically applying a voltage pulse to said two defiection electrodes to drive appropriately charged ink droplets between said electrodes onto said writing medium for reproducing said video signals.

4. In a system of the type wherein ink droplets are successively and uniformly formed and are directed along a path through a charging cylinder for applying a charge to said droplets in accordance with video signals, the improvement comprising a pair of spaced opposed elongated deflection electrodes positioned with one electrode on either side of the path of said ink droplets after passing through said charging cylinder, a first writing medium positioned between one of said electrodes and the path of said ink droplets, a second writing medium positioned between the other of said electrodes and the path of said ink droplets, and means for applying periodically a voltage pulse to said deflection electrodes to drive some of the ink droplets between said electrodes onto said first writing medium and others onto said second writing medium.

5. Ina system of the type wherein ink droplets are successively and uniformly formed and-are directed along a first path through a charging cylinder for applying or not a charge to said droplets in accordance with video signals, the improvement comprising means for establishing a deflecting electric field for deflecting those of Said droplets which are charged by said video signals into a second path while those of said droplets which are not charged by said video signals continue to move in said first path, a writing medium adjacent said second path of said droplets, and means for deflecting periodically the droplets within a predetermined length of said second path onto said writing medium.

6. In a system as recited in claim 5 wherein said means for establishing a deflecting electric field for deflecting those of said droplets which are charged by said video signals into a second path comprises a pair of spaced deflection plates positioned on either side of said first path, a source of direct current potential, and means for applying potential from said source to said spaced deflection plates.

7. In a system as recited in claim 5 wherein said means for deflecting periodically the droplets Within a predetermined length of said second path includes a pair of spaced deflection electrodes positioned on either side of said second path with said writing medium therebetween, said electrodes extending substantially for said predetermined length of said second path, and means for periodically applying voltage pulses to said spaced deflecting electrodes to direct the ink droplets therebetween onto said writing medium.

8. In a system as recited in claim 5 wherein there is included means for applying a charge to said uncharged droplets positioned along said first path at a location subsequent to the deflection of droplets into said second path, another writing medium, and means for deflecting periodically the droplets within a predetermined length of said first path onto said another writing medium.

9. In a system for writing with ink droplets of the type wherein said droplets are regularly formed in a stream and directed along a first path which passes through a charging electrode for applying a charge on each droplet in accordance with the presence or absence of a video signal, the improvement comprising a first pair of deflection plates positioned on either side of said first path and after said charging electrodes, means for applying a constant voltage to said deflection electrodes for establishing a constant electric field therebetween whereby those of said ink droplets which are charged by said charging electrodes are deviated into a second path and the remaining ones of said droplets continue along said first path, a second pair of deflecting electrodes, said second pair of deflecting electrodes being spaced from one another and positioned on either side of said second path whereby ink droplets which are directed along said second path pass between said second pair of deflection electrodes, a writing medium positioned between said second pair of Writing electrodes and adjacent said second path of ink droplets, means for applying voltage pulses periodically to said second pair of deflecting electrodes for deflecting ink droplets therebetween on said paper, and means for ad vancing said paper between said voltage pulses for presenting a fresh surface for the next deposition of ink droplets.

10. A system for writing with ink in response to video signals comprising means for forming a moving single file stream of uniformly spaced ink droplets each having a uniform mass, means for charging or not each of said ink droplets responsive to said video signals, means for directing the ones of said droplets which are charged along a path which is different from the ones of said ink droplets which are not charged, a writing medium positioned adjacent the path of said charged ink droplets, and means for periodically deflecting the ink droplets within a predetermined length of said path onto said writing medium.

11. A system as recited in claim 10 wherein said means for forming a moving single file stream of uniformly spaced ink droplets each having a uniform mass includes oscillator means for synchronizing the forming of said ink droplets together with said video signals and said means for periodically deflecting said ink droplets Within a predetermined length of said path onto said writing medium.

12. A system for writing with ink in response to video signals comprising a source of ink, a movable nozzle connected to said source of ink, means for forcing ink from said source through said nozzle to project ink in a stream along a first path, means for vibrating said nozzle in synchronism with said video signals to form said ink stream into a stream of uniformly spaced, uniform mass ink droplets, means for charging or not each of said ink droplets responsive to said video signals, a first pair of deflection plates positioned on either side of said first path and after said charging electrodes, means for applying a constant voltage to said deflection electrodes for establishing a constant electric field therebetween whereby those of said ink droplets which are charged by said charging electrodes are deviated into a second path and the remaining ones of said droplets continue along said first path, a

second pair of deflecting electrodes, said second pair of deflecting electrodes being spaced from one another and positioned on either side of said second path whereby ink droplets which are directed along said second path pass between said second pair of deflection electrodes, a writing medium positioned between said second pair of Writing electrodes and adjacent said second path of ink droplets, means for applying voltage pulses periodically to said second pair of deflecting electrodes for deflecting ink droplets therebetween on said paper, and means for advancing said paper between said voltage pulses for presenting a fresh surface for the next deposition of ink droplets.

References Cited UNITED STATES PATENTS OTHER REFERENCES Fast Oscillograph Squirts Ink, Electronic Design, Oct.

RICHARD B. WILKINSON, Primary Examiner.

I. W. HARTARY, Assistant Examiner. 

